The invention relates to a fuel supply system for an internal combustion engine with a fuel tank and an activated carbon canister for removing fuel vapors from the tank vent gases.
A fuel supply system of the kind mentioned above is known from DE 199 47 080 C1, in which provision is made for the regeneration of the activated-carbon canister by pressure flushing of the activated carbon canister of an internal combustion engine working with air-assisted direct fuel injection. To this end, the pressure source provided for the air-assisted direct fuel injection is a pressure pump which includes a pressure regulator, and the excess quantity branched off via the pressure regulator is supplied to the activated-carbon canister for the regeneration thereof. The air flushed through the activated-carbon canister is, after being charged with hydrocarbons, returned to the air supply duct adjacent to the inlet module via a regeneration valve. While it is true that such a solution makes it possible, via the lambda probe of the internal combustion engine arranged on the exhaust side, to take the hydrocarbons introduced additionally by virtue of the regeneration of the activated-carbon canister into consideration in the determination of the fuel injection quantities, it is nevertheless tied to pressurized flushing of the activated-carbon canister, and thus requires a pressure pump working with an excess air flow, for the regeneration of the activated carbon canister.
It is therefore the object of the present invention is to provide a fuel supply system of the kind referred to in the introduction, but with which the activated-carbon canister can be flushed both, with positive pressure and with negative pressure, so that the regeneration can be carried out independently of the operating states of the internal combustion engine and of pressure sources, and can, as a result, also be used, with only minor modifications, in connection with internal combustion engines which are operated differently, for example internal combustion engines working with a supercharger.